Due to the depth of the snow in which snowblowers are usually used, snowblowers are typical self-propelled. Snowblowers are hard to manipulate within deep snow because of the weight of the machinery. The deeper the snow is, the harder it is to maneuver the snowblower. Self-propelled snowblowers allow advancement and regression of the snowblower at least partially under the power generated by its engine. The self-propelled snowblowers can be relatively easy to use as compared to non-self-propelled snowblowers. Through the use of self-propelled mechanisms on snowblowers, a user can devote relatively less energy in advancing the snowblower forward and concentrate more energy to steering of the device.
Typically, self-propelled snowblowers have an engine, a pair of drive wheels, an auger, and a discharge chute. The engine provides power to all power-requiring components of the snowblower, which include the drive wheels and the auger. A typical method used to transfer power from the engine to the wheels is using a friction drive that includes a drive pulley, disk, or platter which is rotatably driven by the power produced by the engine. When the friction drive is engaged, an outward side surface of the drive pulley frictionally engages the outer circumferential surface of the wheel or other circumferentially defined surface which is fixedly mounted on the axle or axles that drives the wheels. The user can engage the friction drive byway of a belt tensioning mechanism, which can include one or more belts. In such an arrangement, the belt tensioning mechanism can be actuated by depressing a drive lever located on the handlebar of the snowblower.
A typical auger mechanism in snowblowers can be driven by a worm gear drive which interfaces the auger at a medial portion thereof. Typically, in many two-stage auger mechanisms in which the auger defines a first stage and an impeller defines a second-stage, a shaft is driven by power from the engine. The shaft extends axially through the center of the impeller and rotates the impeller and extends axially outward beyond the impeller. The end of the shaft includes a worm gear which is adapted and configured to rotatably drive a corresponding gear that is keyed or otherwise fixedly connected to a medial portion of the auger. Thus, when the impeller rotates, so does the auger. In such worm gear drive configurations, the medial portion of the auger is not occupied by the auger blade. The engagement means for engaging the auger mechanism is similar to the engagement mechanism for the friction drive. A belt tensioning mechanism is provided that includes one or more belts. These belts are engaged by one or more pulleys that are driven by the engine and transfer power through the belt to the worm gear configuration which then transfers the power to the auger mechanism. The belt tension mechanism for the auger can be actuated through depressing a drive lever located on the handle similar to the drive lever for the friction wheel drive mechanism.
In order to drive both the driven wheels and the auger, two different belt mechanisms must be employed in the typical snowblower. One is used to drive the friction wheel drive mechanism and the other is to drive the auger mechanism. By requiring two different belt mechanisms to be used, a greater chance of mechanical break down within the snowblower is created. Further, a more complicated drive system which requires two different belt systems to drive the components of the snowblower is employed. Also, when the user releases the auger lever used to create tension within the belt mechanism, the auger and the impeller tend to spin until the inertial energy of the rotating parts has suitably been depleted unless a brake or similar device is used. Such an arrangement can prove dangerous for the user and for others in the vicinity of the snowblower.
Therefore, a need exists for a drive system for both the driven wheels and the auger of a snowblower that employs a simple drive mechanism for driving both the driven wheels and the auger mechanism of a snowblower.